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Greg Lewicki And Associates, PLLC <br />11541 WaiThwton Court Phone: (303) 316 -5196 Fax (303) -3=16 -6934 <br />Partwr, CO USA 801323 L- M1lail: info(djewicld.biz <br />July 25, 2012 <br />Marcia Talvitie <br />Colorado Division of Reclamation, Mining, and Safety <br />691 CR 233, Suite A -2 <br />Durango, CO 81301 <br />RE: Post - Mining Topography West of 2700 Road <br />Dear. Ms. Talvitie: <br />RECEIVED <br />JUL 30 2012 <br />Division or Reclamation, <br />Mining and Safety <br />In the Division's letter dated July 16, 2012, you requested further information and justification <br />with regards to the post mining topography west of 2700 Road. Specifically, you expressed <br />concern about the fact that the current and anticipated final topography of some areas west of <br />2700 Road does not match the approved post mine topography in the New Horizon Mine permit, <br />as approved in PR -06. <br />The following are the main reasons for the differences you noted: <br />In -place overburden above the coal is blasted and then hauled from the active mining pit <br />to the mined out pits that need backfilling. Variations in the width of the mining pit from <br />cut to cut can lead to the amount of backfill generated not equaling the amount of backfill <br />required at any given time. This is mitigated as much as practical to minimize backfill <br />problems, but it is not possible to be exact in the backfilling. <br />2. Overburden swell causes an increase in volume due to in place material becoming loose <br />material. While efforts were made to predict the swell factor when the post mine <br />topography was generated for the permit, the actual swell factor will vary from the <br />predicted in some instances that are not possible to completely control or eliminate. <br />Similarly, it is difficult to predict the degree of settling of these materials over time <br />following replacement of the materials. In spite of this lack of predictability, backfilling <br />to a contour that is higher than approved is generally a good practice to guard against <br />creating low spots after settling, which otherwise could potentially interfere with <br />irrigation and cultivation of the land following reclamation. <br />3. The post mine topography in the approved permit is generated from broad mass balance <br />calculations. It is not expected that the actual final topography will be identical to the <br />approved post mine topography. The variations noted are typically on the order of 5 feet <br />(out of an approximate 5700 foot elevation). The rules in the Colorado Coal Program <br />applicable to AOC do not require a particular range of accuracy in predicting final <br />contours, but instead address the existence of slopes on reclaimed land. As shown below, <br />